Fault Tree Manager

The Fault Tree Manager, available starting in Version 2022, allows you to change the analysis type used for multiple fault trees simultaneously. To access the Fault Tree Manager, choose Project > Data Management > Fault Tree Manager.

To use the tool, select the target fault tree analysis type from the New Analysis Type drop-down list. The available options are:

• Equation is the original engine that has been used by all versions of BlockSim; it generates a reliability equation to calculate results.
• Binary Decision Diagram (BDD) is a newer analysis engine that generates a binary decision diagram from the fault tree to calculate results. This newer engine can handle scenarios that the equation method cannot, and generally has better performance than the equation type.
• Approximation BDD is a variant added in Version 2023 that generates a truncated binary decision diagram. This analysis type can handle extreme scenarios that even the regular BDD algorithm cannot. However, this variant is not capable of rendering plots other than the Static Reliability Importance plot.

For more detailed information about the analysis types, see Fault Tree Analysis Types.

The fault trees shown at the bottom of the window are those that currently use whichever type is not selected and are therefore eligible to be changed. Select the diagrams that you want to change and click OK.

Note that changing the analysis type for fault trees that have already been analyzed will reset their analysis status; you will need to reanalyze the diagrams. When the new analysis is performed, the analysis type used for any subdiagrams referenced by the selected diagrams will also be changed, even if you did not select those subdiagrams in the Fault Tree Manager.